This invention relates to a new and distinct cultivar of Portulaca plant, hereinafter referred to by the name `Summer Joy Yellow`. Portulaca `Summer Joy Yellow` is a new variety of Portulaca oleracea. The plant has a vigorous spreading growth habit and can be used as a groundcover. It can also be used in potted or hanging basket presentation. The invention's flowers are yellow with a slight tinge of orange (RHS 17A). The flowers are single and measure 5.2 to 6.0 centimeters in diameter when fully open. There are five distinct petals with an indent at the tip of each petal. Portulaca flowers will typically close under low light and low temperature conditions such as late in the day and at night. `Summer Joy Yellow` Portulaca flowers will stay open later into the evening than most other cultivated varieties. The plant performs well in hot and dry climates. The plant is very resistant to rain, heat and drought.